High explosives



April 23, 1957 'D. BQMQCLOUD ETAL HIGH EXPLOSIVES 2 Shee'ts-Sheet 1 Filed Feb. 25. 1950' mvamoas DON B. McCLOUD 8\ MARY v McCLOUD f g m 1/. Eu;

THEIR ATTORNEY April 23, 1957 o. BJMGGLOUD-ETAL 4 9 HIGH EXPLOSIVESFiled Feb. 25, 1950 asheet -sh et 2 INVHVTOR. DON B. McCLouo &

MARY McC-Loun' THEIR ATTORNEY United States Patent ice HIGH EXPLOSIVESDon B. McCloud and Mary McCloud, Carbondale, 111.; said Don B. McCloudassignor to said Mary McCloud This invention relates to high explosives,more particularly those employing liquid oxygen impregnated carbonaceousmaterial, encased in cartridges, and which are adapted for use inblasting operations where very hard materials such as rock, ore, and thelike, are encountered. This application is a continuation in part of thecopending application of Don B. McCloud and Mary Mc- Cloud, SerialNumber 776,068, filed September 25, 1947, now abandoned, and entitledHigh Explosives.

Liquid oxygen explosive consists of porous, combustible materialssaturated with liquid oxygen, and for brevity known as LOX. In the past,this explosive has been prepared by packing a porous type of carbon suchas lampblack in a cloth bag with an expansible liner or stiffener insidethe bag, then saturating the bag and contents by immersion in liquidoxygen. The porous carbon within the bag absorbs or adsorbsapproximately three and one-half times its weight of liquid oxygen andsuch carbon-oxygen mixture constitutes the high explosive known as LOX.The bag of carbon is commonly called a cartridge and after saturation iscalled a saturated cartridge.

Heretofore, the outside diameter, and the elongated shape of an LOXcartridge, has been governed by the size and shape of a cloth bag usedas an outer covering. An expansible sheath, or liner, when used insideof the cloth bag,has given a certain amount of longitudinal rigidity toa cartridge, but in every case the outer cloth covering or bag has beenthe means of retaining the porous, combustible ingredients within thecartridge, and

such cartridge bag has been free to expand radially to its full elasticlimit. It is necessary to pack or compress the porous, combustibleingredients to certain densities within the retaining medium of acartridge so as to accomplish the desired carbon-oxygen ratio when acartridge is saturated, and inasmuch as the cloth bag constitutes theretaining medium in all previously made cartridges, the size and theshape of thecloth bag determines the size and the shape of thecartridge. The most'widely used filter for cartridges is a type of purelampblack that is exceedingly soft andfiuify in its natural state. Whensuch a filter is compressed in a cartridge, considerable tension is,exerted on the cartridge bag which tends to bulge and stretch to itsexpansible limits. As a result of this, it has been impossible tomanufacture cartridges of uniform, precise outside dimensions on acommercial basis. A type of cotton fabric known as osnaburg is uni-'versally used for cartridge bags, and these bags are made by folding apiece of cloth cut to suitable size and then sewing together one sideand one end of the folded material. A slight deviation in the bag seam,a change in the fibres or weave of the cloth that might influence itsstretching characteristics, or a change in' the pressure required tocompress the carbon content of a cartridge to its required density,cause variations in the diameter, size and shape of cartridges. Theprohibitive cost of heavy, non-stretchable fabric cut and sewed withgreat 110-" 2,789,594 Patented Apr. 23, 1957 curacy, prohibits thecommercial use of bags of this latter yp It is also common practice inthe industry to store cartridges in bins with one row of cartridgesstacked upon another to a considerable height. Cartridges in the bottomlayers of such a pile tend to lose their cylindrical shape due to thepressure on them when a flexible cloth bag is the shaping element.

LOX cartridges of precise and uniform outside dimensions are of greatimportance in modern blasting operations because of the comparativelyrecent development of so-called precision drilling of vertical blastholes into which the explosive is charged. Such holes formerly weredrilled by means of a churn type drill that produced a hole throughraising and dropping a heavy cylindrical shaped tool terminating in arock cutting bit. Blast holes drilled in this manner often wereirregular and hole diameters were not uniform in various types of earthand rock formations, and there was nourgent necessity for precise shapeand dimensions of the cartridges. Comparatively recently, however,rotary drills, similar to those used for oil well drilling, have beenadapted for blast hole drilling. These rotary drills produce smooth,straight blast holes of uniform diameter.

It is advantageous from a blasting standpoint to allow as littleclearance as possible between explosive cartridges andthe wall oftheblast hole in which the cartridges are charged. Blast holes of precise,uniform diameter make it necessary to have similar precision anduniformity in cartridge diameter in order to get maximum results fromblasting, and one phase of our invention is directed to this purpose, aswill be more fully pointed out hereinafter.

Moreover, for the past several years, engineers and scientists, havebeen investigating the peculiar phenomenon exhibited by certain highexplosives known as the Munro effect. It has been demonstrated that theshape of an explosive charge sometimes controls to a large extent thedirection in which a major amount of the forces are exerted whendetonation occurs. It has also been demonstrated'that by shaping the endof an explosive charge in the form of a hollowed-out cone, it ispossible to have much of the explosive force directed away from suchend, in a so-to-speak jet of explosive force. This principle was widelyused during the recent war in the development of explosives known asshaped charges. These shaped charges were used to drill holes in enemypill boxes. The famed bazooka shell was a missile holding a shapedcharge that would drill a hole through the steel shell of an armoredvehicle. These are known examples of the peculiar jet-like forces thatemanate from a properly shaped, hollowed-out surface of a highexplosive. In usual mining or quarrying blast, holes are drilled intotherock at suitable intervals and to suitable depth after which theholes are charged with explosive. Each loaded or charged hole isactually a column imbedded in the rock. Ordinarily, upon detonation, theexplosive charge in each blast hole, exerts its principal forceslaterally in all directions. By utilizing this so-called Munro effect ina manner more fully set forth hereinafter, instead of the evendispersion of the explosive energy as now produced, the explosive forceof a blasting cartridge, individually, or in a column of cartridges, isconcentrated and focused in radial sheet-like zones, which will shatteror fragment the rock or the surrounding material of a blast hole on amuch wider radius than was thought possible.

It is a general object of our invention, therefore, to provide acartridge, especially one containing liquid oxy- I gen-lampblack, whichtakes and retains a precisely acsnug disposition in accurately drilledblast holes, and

A still further object of the inventionis to provide 'a liquid oxygencartridge or container which comprises an' accurately cut blank ofrelatively stiff non-elastic fibrous material, shaped about a mandreltoa true cylinder of the desired diameter, and the meeting edges fixedto preserve the exterior dimensions, the blank also being provided withshaped tongue accommodated in a conical cap secured to the tongues, andhaving an easily ap' plied end closure applicable after filling, and inwhich the securing means of the closure provide a handle ex tension.

Another object of the invention is to provide a high explosive charge,which preferably takes a cylindrical formation, whether it be of theliquid-oxygen lampblack type, or of a shaped or moulded type containingother explosive ingredients, which has impressed or formed in itsexterior surface a plurality of spaced grooves or slots, formed toproduce the Munro effect, along each groove or slot upon detonation ofthe cartridge.

Still another object of the invention is to provide in the liquidoxygcn-lampblack type of the explosive, and other types as well, theMunro effect grooves, which are impressed and retained in the explosivematerial through the formation of the cartridge itself, and wherein thecartridge is of the type which takes and retains the configuration anddimensions necessary for ready insertion into accurately drilled blastholes.

Still another object of the invention is the provision of cartridges ofthe type referred to, which may be dropped one after the other into ablast hole and wherein the Munro effect grooves assume a haphazardalignment longitudinally, and deliver the Munro effect substantially toany portion of the wall of the blast holes sur rounding the superposedcartridges.

In order to obtain the Munro effect" the grooves must have certaincharacteristics. ordinarily defined by a pair of flat side walls whichmeet at an apex and the angle at this apex should be no greaterth'anninety degrees and no less than fortysfive degrees. Thus, thepermissible range of the angle at the apex is from forty-five to ninetydegrees.

Another feature which is of critical importance is the ratio of thedistance from the axis or center of'the charge to the apex of any grooveas compared to the distance across the mouth or open side of the groove.The dis tance from the center to the apex of the groove must .be atleast one and one-half times the distance across the mouth of the grooveand no greater than three times, the distance across the mouth of thegroove.

An important object of the present invention is to pro.- vide acartridge of the general character above indicated which is of generallycylindrical formation having longitudinal grooves in the cylindersurface and which grooves fulfill the specifications above outlined. V.

In order for the cartridge to have the Munro effect, it is alsoessential that the explosive be. of a closely compacted nature. Aliquid-oxygen explosive is entirely satisfactory and any other explosivewhich might besubstituted therefor must be of a closely compacted naturesuch as that provided by the explosives which are melted and formed insolid shape.

Certain types of commercial blasting, portiens reguireg Each. of thesegrooves" is that the explosive force be downwardly directed over a widearea.

In view of this condition a furtherobject is to provide an explosivecartridge of the general character above outlined which takes the formof a rectangular block having one face formed with grooves having thecharacteristics above outlined and which grooves will impart to thecartridge the shaped charge effect. In use such a cartridge is placedwith the grooves faced downwardly in engagement with the surface whichis to be shattered. These grooves will result in a shaped charge effectgiving high penetration and good shattering effects.

Other and. further objects of the invention-will appear from thespecification and claims hereinafter following, and from theaccompanying drawings forming a part hereof, and in which:

Figure 1 is a side elevational view of the completed high explosivecartridge forming the subject matter of the invention.

Figure 2 is an enlarged transverse sectional View, correspondingsubstantially to the line 2-2 of Figure 1.

Figure 3 is a transverse sectional view of the explosive charge, similarto Figure 2, but shown with the cartridge or casing omitted.

Figure 4 is a plan view of the blank from which the body portion of thecartridge is constructed.

a Figure 5 is a sectional view through the blank shown in Figure 4, andcorresponding substantially to the line 5'--.-5 of Figure 4.

' Figure 6 is a plan view of a blank from which the nose portion of thecartridge is constructed.

Figure 7 is a perspective view of the blank shown in Figure 6 in itsassembled condition.

Figure 8 is a diagrammatic view illustrating one limit of thepermissible range as to the angle at the apex of the grooves and theratio between the distance from the center to the apex of a groove tothe distance across the mouth of'a groove.

Figure 9 is another diagrammatic view bringing out the other limit as tothe angle of the apex of the grooves and the ratio above identified.

Figure 10 is a cross section through a modified form of cartridge; and

Figure 11 is a diagrammatic view of the charge shown in Figure 10.

As shown in the drawings, the embodiment of the invention comprises ablank 10 of predetermined length and breadth,rhaving side marginal edges11 and 12. At one end the blank is provided with a plurality oftriangular tongues 13, and the blank 10 is slightly scored along thebase, portions of the tongues 13, as at 14, to enable the tongues 13 tobe readily bent inwardly'toward' each other for a purpose which willpresently appear. The opposite end of the blank 10 is cut offsquare withthesides 11' and 12,-as indicated at 15. Fixed to one face of the. blank10, as by suitable adhesive, is a corrugated sheet or liner 16, thecorrugations 17 of which are disposed longitudinally of the sheet and ofthe blank 10. The corrugations'17 preferably extend the full length ofthe blank 10, and at one set of ends terminate at the line of scoring14, the opposite ends of the corrugations 17 terminating flush with theopposite end 15 of the blank 10. The corrugated sheet 16 also terminatesshort of theouter edge of the marginal portion 11 of the blank 10, and agreater distance from the outer edge of the marginal portion '12 of theblank 10. In crosssection the corrugations 17 are triangular in shape,the crests 18 thereof being uniformly spaced apart, and definedbetween-the crests 18, are valleys or grooves 19, the walls-2t) of whichdiverge outwardly toward the crests 18. I The: blank 10 and the attachedcorrugated sheet or lininglfi, may bemade of heavy kraft paper,chipboard, strawboard, plastic, or any other sheet material having thenecessary strengthand inelasticity.

As before pointed out, the blank,.10 andthelcormgated sheet ,16 are ofpredetermined .dimensions,- dependent sees-ear upon the diameter andlength ofthe cartridgeto'be c'onstructed. The blank 10, with itsattached corrugated sheet or liner 16, is adapted to be disposed about acylindrical form or mandrel (not shown) of exact pre-determineddimensions, so that the blank may be wrapped about the form or mandrel,with the liner 16 inside, until the opposite side edges of the sheet 16meet and abut, while the marginal portions 11 and 12 of the sheet 10will be overlapped. The margins 11 and 12 are then secured by suitablemetallic clips or fasteners 21, thereby fixing the outside diameter ofthe body portion 22 of the cartridge 23, and disposing the corrugations17 side by side continuously around the insidediameter of the cartridge23. Upon removal of the formed or shaped cartridge cylinder from themandrel, it will present a continuous inelastic wall held againstexpansion by the metallic fasteners 21.

In this condition the tongues 13 may be bent inwardly along the scoring14, to define a conical nose portion adapted to be accommodated within acone-shaped nose piece 24, secured to the tongues 13 by fasteners 25.The nose piece 24 is preferably made up from a blank 26, of suitableinelastic material similar to that constituting the body portion 22 ofthe cartridge 23. As best shown in Figures 6 and 7 the blank 26 ispreferably in the form of a cutout disk, cut out, as at 27, to define atongue 28, and a slit 29, so that when the blank 26 is rolled up, thetongue 28 may be inserted into the slit 29 and locked in the slit tomaintain the blank 26 in hollow conical shape,

adapted to overlie the tongues 13, and to be secured to the tongues 13by the fasteners 25.

The cartridge 23 is now ready to be filled with carbonaceous material,in this embodiment, a particular grade of larnpblack such as thatheretofore referred to. The

lampblack is introduced into the open rear end of the cartridge 23, andbeing of a loose powdery character, flows into the cartridge 23 and inand about the corrugations 17, and afterward, being tamped or pressedwithin the cartridge, the shape of contour of the corrugations 17 areimpressed in the exterior surface of the charge in the form oflongitudinally extending slots or grooves of triangular formation. Whencompletely filled and packed, a closure 30, in the form of a disk, maybe inserted within the rear end of the cartridge 23, and a strand ofWire 31 extended through the wall of the cartridge in position tooverlie the closure 23 and hold it in place. The ends of the wire 31 maybe extended, and interwound, to form a handle .32 bywhich the cartridge23 maybe readily carried.

The cartridge 23, when thus assembled and fully packed, r

is" immersed in liquid oxygen for a pre-determined petied, and tofacilitate or hasten the impregnation of the carbonaceou material Withinthe cartridge by the liquid oxygen, the body portion of the cartridge isprovided with a plurality of pin holes 33 of extremely small size, ofthe order of the interstices between the fibres of a woven fabric.

1 The charge'of explosive, proper, shown in Figure 3 apart from thecartridge itself, has an elongated body portion 34, generallycylindrical in shape, and its exterior surface is "characterized by aplurality of longitudinally extending grooves or slots 35, spaced apartby the intervening defining ridges or crests 36, each groove or slot 35having walls 3737 which extend from a point below the exterior surfaceof the charge, in divergent relation toward the exterior surface of thecharge, thus providing a, plurality of extended cavities or depressions,which upondetonation of the charge, exert the so-called Munro e ife'ctin a plurality of longitudinally extending radially directed zones ofconcentrated or intensified explosive effect. In this connection, itwill be clear that though the charge proper, described in connectionwith Figure 3, requires the cartridge 23 to retain the same in unitaryformation, nevertheless the invention contemplates the formationof"a""charge from other explosive ingredi nts; which may be molded orotherwise formed to provide a] unitary charge, characterized by theslots or grooves already referred to, and which produce the so-called-Munro effect upon detonation of the charge.-

corrugation is represented at c and the'distance from the apex a to thecenter or axis of the cartridge which is depicted at o is represented byd. In Figure 8 d is three times as great as c which is one limit forthis ratio.

' In Figure 9 the reference characters a, b, c, and -d depict the sameelements that are illustratedin Figure 8. However, in Figure 9 the angleb is forty-five degrees which is the smallest permissible angle.

Moreover, d is one and one-half times 0.

Briefly summing up at this point, his noted that the, angle bhas apermissible range of from forty-five to ninety degrees. Moreover, d mustbe from one and one. half to three times as great as c.

Referring to Figures 10 and 11, a modified form of the invention istherein illustrated. The charge is shown as being of generallyrectangular formation including an upper face 40, a lower corrugatedface 41, and side faces 42 and 43. These faces are preferably defined bya. cardboard casing or one of comparable material which enclosestherewithin the explosive material represented at" 44. This material ispreferably the carbon which is saturated with liquid oxygen. cludes aplurality of corrugations 45 which are in all respects similar to thecorrugations 17 in the form of Figure 2.

As shown in Figure 11, the angle at the apex of one of the corrugations45 is represented at e. The distance across the mouth of one of thecorrugations is indicated at g and the distance from the apex to theface 40 is indicated at f. In accordance with the principle abo'veexplained, the angle e has a permissible range of fortyfive to ninetydegrees and the distance f must be from one and one-half to three timesthe distance g.

The explosive charge shown in Figure 10 is intended to be used byplacing the corrugated face 41 downwardly and in engagementwith asurface to be shattered. Upon detonation the corrugations 45 give theshaped charge effect which results in greatly improved penetratingeffects.

- Through the arrangement described, the high explosive cartridge isprovided having a constant pre-determined diameter before and afterfilling and packing and after. saturation with liquid oxygen, renderingthe same suitable for insertion into accurately drilled blast holes, andby reason of the formation of the charge itself, upon detonation, thecharge of explosive will exert the so-called Munro effect radially in aplurality of extended zones. Additionally, When the cartridges arepacked haphazardly' one on top of another in a blast hole, the column ofexplosive will exert its effect upon the wall of the blast hole radiallyin all directions.

Although the preceding description of the invention has been directed toexplosives and explosive cartridges of cylindrical formation, andconsequently of the type most used in commercial blasting operations,the invention ob: viously is not limited to cylindrically shapedexplosivecharges or explosive cartridges. Sometimes explosive chargesare used to break boulders by a method known in the mining industry asmud capping," adobe blasting or bulldozing, which consists in placing anexplosive charge on the surface of a boulder, covering the charge withmud or dirt, and then detonating the charge. The force of the explosionthat strikes the surface of the boulder often is sufi'icient to breakthe boulder into pieces In Figure 8 this angle b The corrugated face 41in-,

agree- 50a qf-asize--which mayreadily be handled. For this type ofblasting an explosive chargewhich will present a flat surface next tothe boulder would -bemore eifeetive than a cyli-nd rically shapedcharge, because the explosive force emanates from the surface of thecharge.

Thus in one adaptation of the invention the explosive charge would he ofelongated box-like form, rectangular instead of circular in crosssection, and encased in a boxshaped ribbed cartridge, similar to thecartridge 23, with the projections or ribs inwardly disposed. In packingsuch a cartridge, itmay be placed in a form to prevent distortion whencarbonaceous material is compressed Within it to the proper density, andafter removal satu-' rated with liquid oxygen. The explosive chargewithin the container; will thus comprise a rectangular block havingV-shaped grooves like the groove 35, along each flat surface, other thanthe ends, which will give directional force to the energy released bytheexplosion in a manne'r" already referred to. In addition to cylindricaland box-like shapes mentioned, other shapes might be used, but in eachcase the explosive will include a plurality of \f-shaple'd slots orgrooves of the character already described in detail.

While we have illustrated and described the preferred formof-construction for carrying our invention into effct, this-is capableof variation and modification without departing from the spirit of theinvention. We, therefore,do not wish to be limited to the precisedetails of construction set forth, but desire to avail ourselves of suchvariations and modifications as come within the ease of the appendedclaims.

What is claimed is: I j

w 1. An explosive charge of generally cylindrical formatioii havinglongitudinally extending closely adjacent corriigat ions formed in itsperiphery, said corrugations being defined by grooves having side wallswhich meet at apices and open mouths with the side wall of one groovemeeting. the side wall of the next adjacent groove, the an'gle'betweenthe side walls at each apex ranging from forty-five to ninety degreesand the distance from the center of s'aid charge to each apex being fromone and one-half to three times the distance across the mouth of one ofthe grooves, said explosive charge being of a closely compactedhomogeneous explosive material having high detonating properties.

2. An explosive charge of generally cylindrical formation having aplurality of longitudinally extending closely a'djacent corrugationsdefined by a plurality of grooves with each groove" being ofsubstantially the same size and snapeas any other groove, each of saidgrooves having a pair of side walls which meet at an apex and an openmouth with the side walls of every groove meeting the walls'of the nextadjacent grooves, the angle between the side walls at each apex rangingfrom forty-five to ninety degrees and the distance from the center ofsaid charge to each apex being from one and one-half to three times thedistance across the mouth of one of the grooves, said explosive chargebeing of a closely compacted homogeneous liquid oxygen explosivematerial having high detonating properties.

3. A liquid oxygen explosive charge of generally cylifidrical formationhaving longitudinally extending closely adjacent corrugations formed inits periphery, sai'clcorrugations being defined by grooves having sidewalls meet at apice's and open months With the side walls of everygroove meeting the side walls of the urea adjacent grooves, the anglebetween the side walls zit-each apex ranging from forty-five to ninetydegrees andthe distance from the center of said charge to each apexbeing from one and one-half to three times the distance acrossthe mouthofoneofi the grooves, and a cylindrical casing enclosing said chargewith said corruga tionsin engagement withthe inner face of said casing.

4. A detona-ti ng. explosive charge of generally cylindricalformationhaving. a plurality of longitudinally extending closelyadjacent corrugations defined by a plurality of grooves with each groovebeing of substantially the same size andshape as any other groove, eachof saidgrooveshaving a pair of side walls which meet at an apex and anopen mouthwit-h: the sidewalls of every groove meeting the side walls ofthe next adjacent grooves, the angle between the side walls at each apexranging from forty-five to ninety degrees and the distance from thecenter of" said charge to each apex being from one and one-half to threetimes the distance across the mouth of one of the grooves,.s'aid'explosive charge comprising carbon saturated with liquid oxygen toprovide a closely compacted mass. 1

5. In combination, an outer cylindrical casing, an innor casing havingcorrugations engaging. the, inner face of said' ou't'er casing, saidcorrugations being defined by longitudinally extending grooves with allof the grooves of substantially the same size and shape each of saidgrooves having side Walls which meet at an apex and an opeh'rhouth withthe side walls of every groove meetingthe' sidewalls of the next"adjacent groove, the angle between the side Walls at said' apex rangingf om fortyfive to" many degrees and the distance from said apex to thecenter ofsaid' inner casing being from one and onehalf to threetime's-the distance across the mouth of one of'th'e grooves, and aclo's'ely'conipacted homogeneous explosive material having highdetonating properties compltely' fillin v said" inner cas'ing.

6. In combination, an outer cylindrical casing, an inner casin'ghavingcorrugations engaging the inner face of said outer casing, s'ai'd'corrugations being defined by longitudinally extending grooves with allof the grooves of substantially the same size and shape, each of saidgrooves having side walls which meet at an apex and an open mouth withthe side walls of every groove meeting the side walls of the'nextadjacent groove, the angle between the sidewalls at said apex rangingfrom forty-five to ninety degreesand the distance from said apex to thecenter of said inner casing being from one and one-half to three timesthe distance across the mouth of one of the grooves, and carbonsaturated with liquid oxygen completely filling said inner casing.

References Cited in the file of this patent UNITED STATES PATENTS1,923,496 McCloud m; Jan. 1, 1935 2,409,343 Grenlick r Oct. 22, 19462,494,256 Musket et a1. Jan. 10, 1950 2,543,057 Porter Feb. 27, 1951FOREIGN PATENTS 369,237 Italy Mar. 15, 1939 579,279 Great Britain July30, 1946 921,405 France Jan. 13, 1947 618,617 Great Britain Feb. 24,1949 622,062 Great Britain Apr. 26, 1949 OTHER REFERENCES Sukha'revsky:VoinaiTekhnika,'vol. 253 (1926),.No. 39, pages 18 to 24 and 8 sheets ofdrawings. (Copy in Div. 70.) Unofiicial translation available in Div. 70(16 pages of text and same 8 sheets of drawings).

Birkhotf et al.: Journal of Applied Physics, vol. 19, No. 6, pages563-582, particularly page 565 (June 1948). (Copy in ScientificLibrary.)

